boXem A series

[boXem]

Thanks. So, if a person got the A 4216/E5 vs the E4 or E3, they shouldn't see a drop in power even across a 2Ω impedance on any channel?

Indeed

 

[rsg]

Is it possible to increase the gain on the A series to 29 dB by using a different Hypex Switch Mode Power Supply?

 

[boXem]

Is it possible to increase the gain on the A series to 29 dB by using a different Hypex Switch Mode Power Supply?

The power supply is chosen to output a voltage as close as possible to the maximum accepted by the module. This will determine the maximum power of the amplifier.
Then the gain stage is configured in order to be able to reach the maximum power with a given input, 2 and 4 V on our case.
Is there a specific reason that would bring you to need a 29 dB gain?

 

[rsg]

The power supply is chosen to output a voltage as close as possible to the maximum accepted by the module. This will determine the maximum power of the amplifier.
Then the gain stage is configured in order to be able to reach the maximum power with a given input, 2 and 4 V on our case.
Is there a specific reason that would bring you to need a 29 dB gain?

To match the gain of my Class A/B amplifiers and to overcome the input sensitivity of 2V. Input sensitivity of Class A/B is closer to 1.5-1.6V. I would have to drive my pre-amp/processor less to attain the same SPLs.

 

[boXem]

To match the gain of my Class A/B amplifiers and to overcome the input sensitivity of 2V. Input sensitivity of Class A/B is closer to 1.5-1.6V. I would have to drive my pre-amp/processor less to attain the same SPLs.

I am not sure if this is the best strategy for good sound. The higher the pre-pro output, the better it's SNR. And a pre-pro doesn't care about the gain differences between amplifiers since it already has to overcome the differences between speakers sensitivity.
That said, if you feel more comfortable with more gain, I perfectly respect this and would like to let you know that the A 5519/Nx allow a gain of 29 dB with the optional buffer.

 

[rsg]

What would be the disadvantages of an optional buffer aside from cost? In terms of THD across 20-20KHz, noise floor, SNR & reliability over 10+ years?

 

[rsg]

I believe the THX standard for audio amps is 29 dB voltage gain using a reference near 1.6V RMS. I could be wrong & will be happy to be corrected.

 

[boXem]

What would be the disadvantages of an optional buffer aside from cost? In terms of THD across 20-20KHz, noise floor, SNR & reliability over 10+ years?

The optional buffer is better than the standard one with 26.5 dB gain. Lower THD, lower noise, higher SNR. Reliability should be the same

 

[amper42]

The optional buffer is better than the standard one with 26.5 dB gain. Lower THD, lower noise, higher SNR. Reliability should be the same

So the optional buffer offers lower noise and higher SNR at 29dB than the standard buffer at 26.5dB? Is there an up charge for this option? If so, how much? Which amp designs can it be used on? Thank you!

 

[boXem]

So the optional buffer offers lower noise and higher SNR at 29dB than the standard buffer at 26.5dB? Is there an up charge for this option? If so, how much? Which amp designs can it be used on? Thank you!

Talking here from the optional buffer for the NCx500 based A 551x/Nx, compared to the buffer embedded in the NCx500.
The optional buffer for the A 551x/Nx is indeed the standard one for the A 42xx/Ex with a different gain resistor.

 

[Oniiz86]

Question is to provide a completed amplifier worth the modules it embeds. People pay a significant amount of money for an ultra high performance amplifier, I want them to have the product they paid for.

Max power is 210 W with an SMPS1200A400, so optimal gain is 20.4/26.4 dB.
The values you see on the measurements are lower than this for two reasons :
- measurements were done with a gain stage designed for the 1ET400A, so missing 0.5 dB. The production boards will have enough gain, which may degrade the results by 0.2-0.2 dB.
- the gain value REW calculates depends from the accuracy of the full scale in/out voltages entered as parameters and I have to admit that I didn't spend a lot of time on calibrating ultra accurate values

I was wondering if you could share some measurements with the 1ET6525SA's input buffer as the previous tests were based on the 1ET400A's input buffer, also with your Arthur 4216/E2 & A 4216/E2 1ET6525SA based models will they both share the same gain settings of 20.3dB/26.3dB because the previous Arthur 4215/E2 & A 4215/E2 1ET400A based models had differing gain settings of 20.8dB/27.2dB & 24.3dB/30.5dB respectively?

 

[boXem]

I will do so when some I find some time. Only two resistors are slightly changed, so the FFT will look strictly the same. Amplified upstream noise will increase by the gain increase, so SINAD will decrease by the same value.
Both Arthur 4216/E2 and A 4216/E2 have a gain of 20.3/26.3 dB